JP2002076759A - Antenna reflecting mirror - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve highly efficient antenna characteristics by achieving highly efficient antenna axial ratio. SOLUTION: A reflecting mirror 10 is formed by dividing a mirror face into the first to the seventh mirror face divisions 101 to 107. The first, the second and the fifth mirror face divisions 101, 102 and 105 and the third and the fourth mirror face divisions 103 and 104, and the sixth and the seventh mirror face divisions 106 and 107 are so constituted that they are made of conductive mesh material 12 whose amount of reflection varies depending on the polarization direction of the incident wave, and so that their dependence on the polarized wave direction are different from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna reflector used, for example, as a ground station or mounted on a spacecraft such as an artificial satellite.

[0002]

2. Description of the Related Art Conventionally, as an antenna reflector mounted on a spacecraft such as an artificial satellite, a conductive mesh material in which conductive fibers such as a metal material are woven into a mesh by tricot knitting is stretched in a mirror shape. As a result, a mirror which can be folded and unfolded to facilitate transportation to outer space has been developed. As such an antenna reflecting mirror, for example, JP-A-7-226620 is known.

By the way, such an antenna reflector is
While lightening can be achieved and easy transportation is possible, the conductive mesh material constituting the mirror surface, if the polarization direction of the incident wave incident on the mirror surface is different according to the woven mesh direction And a so-called anisotropic characteristic in which the amount of reflection (the amount of transmission) changes. Therefore, for example, when a circularly polarized radio wave is incident, the amount of reflection differs in the polarization direction, the axial ratio of the radiation pattern is degraded, and the antenna characteristics are degraded.

However, in the above-mentioned antenna reflector, it is necessary to prevent the deterioration of the antenna axial ratio by setting the mesh of the conductive mesh material as small as possible and setting the transmission amount of the incident radio wave to be small. In addition, there is a problem that the production including the design is very troublesome. Also, when the frequency increases, it is necessary to further reduce the mesh, and it becomes difficult to manufacture an antenna with good characteristics.

[0005] In such circumstances, as an anisotropic material in which the amount of reflection changes when the polarization direction of the incident wave is different, various kinds of anisotropic materials are not limited to antenna reflectors in which a conductive mesh material is stretched into a mirror surface. The same applies to the case where a mirror surface is formed using an isotropic material.

[0006]

The conventional antenna reflector has a problem that the production including its design is very troublesome if the antenna axial ratio is prevented from deteriorating.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a simple structure, which can achieve a high efficiency of the antenna axial ratio, and which can realize high efficiency antenna characteristics. The purpose is to provide a mirror.

[0008]

SUMMARY OF THE INVENTION According to the present invention, there is provided an anisotropic material in which the amount of reflection changes when the polarization direction of an incident wave is different, and the direction of polarization of at least a part of the mirror surface is changed to another mirror surface. The antenna reflector was provided with a reflector surface set differently from the above.

[0009] According to the above construction, the reflection mirror part has a mirror surface partly different in the direction of polarization dependence of the other mirror surface, thereby reducing the change in the transmission amount (reflection amount) due to the difference in the polarization direction of the incident wave. And uniformity can be achieved. Therefore, even when the incident wave is a circularly polarized wave, a change in the transmission amount (reflection amount) can be reduced, whereby prevention of deterioration of the antenna axial ratio can be promoted and antenna characteristics can be improved.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows an antenna reflecting mirror according to an embodiment of the present invention. The reflecting mirror surface 10 includes, for example, first to seventh divided mirror surfaces 101, 102, 103,
4, 105, 106, and 107 are combined to form a desired shape. The first to seventh divided mirror surfaces 101 to 101
Each of the members 107 is configured to be substantially foldable and deployable via a support structure 11 in which a beam member is framed and connected in a substantially hexagonal column shape, as shown in FIG. 2, for example.
Then, the first to seventh divided mirror surfaces 101 to 107
The whole is integrally foldable and deployable to a mounting structure such as a spacecraft body (not shown).

The first to seventh divided mirror surfaces 101 to 1
The reference numeral 07 denotes an anisotropic material whose reflection amount changes on one mirror surface of each support structure 11 when the polarization direction of the incident wave changes, for example, the conductive mesh material 12 has a different mesh direction (braiding direction). Then, it is stretched to a desired mirror shape via a mesh support structure (not shown), and is stretched to a desired antenna mirror shape as a whole. These conductive mesh materials 12
Are respectively folded or expanded in a mirror shape in conjunction with the folding and unfolding of the first to seventh divided mirror surfaces 101 to 107.

That is, the conductive mesh material 12 is a wire material 12 in which a metal material wire such as a molybdenum wire is plated with gold.
3, for example, as shown in FIG. 3, is formed by knitting in a well-known tricot knit or the like.

The conductive mesh member 12 has a mesh supporting structure such that the mesh direction (braiding direction) is, for example, the same in the first, second and fifth divided mirror surfaces 101, 102 and 105. (Not shown)
It is stretched through. In addition, the conductive mesh material 12
The other third and fourth divided mirror surfaces 103 and 104, and the sixth and seventh divided mirror surfaces 106 and 107 have a mesh support structure (not shown) such that their mesh directions (weaving directions) differ by, for example, 60 °. ) Is stretched to a desired mirror surface shape.

The angle of inclination of the conductive mesh material 12 in the mesh direction is not limited to the above-mentioned angle of inclination, but is appropriately set according to the mirror structure or the like.

Here, when the mesh direction of the conductive mesh material 12 is substantially parallel to the vertical electric field EV of the incident wave, the transmission amount of the vertical electric field EV becomes small, and the horizontal electric field EH
Is increased.

In the above configuration, the first to seventh divided mirror surfaces 101 to 107 are formed by the action of the conductive mesh material 12 so that the third and fourth divided mirror surfaces 103 and 104 and the sixth
The direction in which the incident wave is dependent on the polarization of the split mirror surfaces 106 and 107 is different from the direction in which the first, second and fifth split mirror surfaces 101, 102 and 105 are dependent on the polarization.

When radio waves arrive, the first to seventh radio waves
The transmission amount (reflection amount) of each of the divided mirror surfaces 101 to 107 is set according to the polarization direction of the incident wave. As a result, when the incident wave is a circularly polarized wave, the first to seventh divided mirror surfaces 101 to 107 are kept to a minimum change in the transmission amount (reflection amount) as a whole.

As described above, the antenna reflecting mirror includes the first
The first, second, and fifth divided mirror surfaces 101, 102, and 105 and the third and fourth divided mirror surfaces 103, 104, the sixth, and the seventh divided mirror surfaces 101 to 107 are formed.
When the polarization direction of the incident wave is different from the divided mirror surfaces 106 and 107, the conductive mesh material 12 whose reflection amount changes is configured such that the direction of dependence on the polarization is different.

According to this, the first to seventh divided mirror surfaces 1
In Nos. 01 to 107, the directions of dependence on the polarization are different, so that the change in the transmission amount (reflection amount) due to the difference in the polarization direction of the incident wave can be reduced, and uniformization can be achieved.

Therefore, even when the incident wave is a circularly polarized wave, the change in the transmission amount (reflection amount) can be reduced, thereby preventing the deterioration of the antenna axial ratio and promoting the antenna characteristics.

In the above embodiment, the case where the conductive mesh material 12 is used as the anisotropic material whose reflection amount changes when the polarization direction of the incident wave forming the mirror surface is different has been described. However, the present invention is not limited to this, and can be applied to a mirror surface structure using another material.

In the above-described embodiment, the first to seventh embodiments
In the divided mirror surface structure using the divided mirror surfaces 101 to 107, the first, second, and fifth divided mirror surfaces 101, 102, and 105 are used.
The third and fourth divided mirror surfaces 103, 104, and the sixth
The description has been given of the case where the mesh directions of the seventh divided mirror surfaces 106 and 107 are different, but the present invention is not limited to this configuration, and all the mesh directions of the first to seventh divided mirror surfaces 101 to 107 are different. In any case, substantially the same effect can be expected by appropriately setting according to the incident wave. The split mirror structure is not limited to the seven-segment mirror structure, but can be applied to mirror structures having other numbers of divisions.

Further, the mirror structure is not limited to the split mirror structure. For example, even in a single mirror structure, a part of the conductive mesh material 12 stretched on the mirror surface is partially replaced by another mirror surface portion. By configuring so as to have different mesh directions, substantially the same effect can be expected.

In the above-described embodiment, the first to seventh embodiments
Although the description has been given of the case where the support structure 11 of the divided mirror surfaces 101 to 107 is configured to be foldable and expandable, the present invention is not limited to this. For example, it is also possible to apply a configuration using a support structure having a fixed structure. Similar effects can be expected.

Therefore, the present invention is not limited to the above-described embodiment, but can be variously modified in the implementation stage without departing from the scope of the invention. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

For example, even if some components are deleted from all the components shown in the embodiment, the problem described in the section of the problem to be solved by the invention can be solved, and the effects described in the effects of the invention can be solved. Is obtained, a configuration from which this configuration requirement is deleted can be extracted as an invention.

[0028]

As described above in detail, according to the present invention, an antenna having a simplified structure, high efficiency of the antenna axial ratio and high antenna characteristics can be realized. A reflector can be provided.

[Brief description of the drawings]

FIG. 1 is an arrangement configuration diagram for explaining a schematic configuration of an antenna reflecting mirror according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a configuration example of a support structure of FIG.

FIG. 3 is an enlarged configuration diagram showing a knitted state of the conductive mesh material of FIG. 1;

[Explanation of symbols]

 10 ... Reflecting mirror surface. 101: First split mirror surface. 102: Second split mirror surface. 103: Third split mirror surface. 104 Fourth divided mirror surface. 105 5th divided mirror surface. 106: Sixth divided mirror surface. 107 7th divided mirror surface. 11 ... Supporting structure. 12 ... conductive mesh material. 121 ... wire rod.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01Q 15/20 H01Q 15/20 F term (Reference) 5J020 AA03 AA07 BA05 BA09 CA04 DA02 5J046 AA03 AA07 AB15 DA02 DA06 KA03 KA04

Claims (4)

[Claims] 1. A reflecting mirror surface which is formed of an anisotropic material whose amount of reflection changes when the polarization direction of an incident wave is different, and in which at least a part of the mirror surface has a direction dependent on the polarization different from that of the other mirror surface. An antenna reflecting mirror comprising: 2. The reflecting mirror surface is formed of a plurality of split mirror surfaces, and at least one of the plurality of split mirror surfaces is set to have a polarization dependent direction different from that of other split reflecting mirrors. The antenna reflector according to claim 1. 3. The antenna reflector according to claim 1, wherein the anisotropic material is a conductive mesh material obtained by weaving conductive fibers into a mesh. 4. The antenna reflecting mirror according to claim 1, wherein the reflecting mirror surface is configured to be foldable and expandable.